Dr. Theodore Colton will head the Statistics core that will assist with study design and data analysis, particularly of Project 1 (Condom promotion interventions for STD Clinic patients), 2 (The role of C trachomatis in endometrial causes of infertility) and 6 (Humoral and cellular immune responses in gonococcal disease). This core will determine sample sizes needed for adequate power; it will provide computerized data management services and final analysis in the cleanup phases of projects.